Delivery System for a Valve Prosthesis

ABSTRACT

A heart valve prosthesis and delivery systems are provided for replacing a cardiac valve. The heart valve prosthesis includes a self-expanding frame includes a portion having a crimp that provides additional flexibility to the self-expanding frame in the collapsed configuration.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. Apple. User. No. 13/658,044,filed Oct. 23, 2012, now U.S. Pat. No. 9,226,823 the disclosure of whichis incorporated by reference herein in its entirety.

FIELD OF THE INVENTION

The present invention is related to a heart valve frame. Morespecifically, the present invention is directed to a valve prosthesis.

BACKGROUND OF THE INVENTION

Cardiac valves exhibit two types of pathologies: regurgitation andstenosis. Regurgitation is the more common of the two defects. Eitherdefect can be treated by a surgical repair. Under certain conditions,however, the cardiac valve must be replaced. Standard approaches tovalve replacement require cutting open the patient's chest and heart toaccess the native valve. Such procedures are traumatic to the patient,require a long recovery time, and can result in life threateningcomplications. Therefore, many patients requiring cardiac valvereplacement are deemed to pose too high a risk for open heart surgerydue to age, health, or a variety of other factors. These patient risksassociated with heart valve replacement are lessened by the emergingtechniques for minimally invasive valve repair, but still many of thosetechniques require arresting the heart and passing the blood through aheart-lung machine.

Efforts have been focused on percutaneous transluminal delivery ofreplacement cardiac valves to solve the problems presented bytraditional open heart surgery and minimally-invasive surgical methods.In such methods, a valve prosthesis is compacted for delivery in acatheter and then advanced, for example, through an opening in thefemoral artery and through the descending aorta to the heart, where theprosthesis is then deployed in the aortic valve annulus.

During delivery, the delivery system including the valve prosthesis mustbe advanced through multiple bends in the patient's vasculature. Somevascular bends will straighten as the relatively stiff delivery systemis passed through. However other vascular bends, e.g. the aortic arch,cannot be straightened. Therefore, a typical delivery system bends in asingle plane and kinks, or folds onto itself, when advanced through asubstantial vascular bend in order to traverse the bend. This bending ofthe delivery system is presently routine during delivery of the valveprosthesis frame. Bending of the delivery system allows for a longervalve prosthesis frame that can be anchored in the aortic annulus andthe ascending aorta.

A typical valve prosthesis frame is made of self-expanding metals, suchas Nitinol. The metal structure of the nitinol holds the compressedframe into a tubular structure which resists bending and kinking. Thus,bending, flexing, and/or kinking the valve prosthesis and deliverysystem during tracking and delivery typically requires a large amount ofbending force.

In view of the foregoing, it would be desirable to provide a valveprosthesis that is capable of conforming to a patient's anatomy whileproviding a uniform degree of rigidity and protection for critical valvecomponents. Protection for critical valve components is essential tomaintain reliability for the valve prosthesis. In addition, it would bedesirable to provide a delivery system that facilitates bending of thedelivery system around a bend and a valve prosthesis that includes aflexible region that is present when the valve prosthesis is compactedfor delivery.

BRIEF SUMMARY

Provided herein are valve prostheses that generally include aself-expanding frame, where the valve prosthesis is sutured to theself-expanding frame. Such configurations achieve numerous goals. Forexample, such configurations can: prevent the native leaflets fromobstructing flow through the left ventricular outflow tract (LVOT);prevent the native leaflets from interacting with the prostheticleaflets; recruit the native leaflets in minimizing perivalvular leaks;maintain proper alignment of the valve prosthesis; avoid systolicanterior mobility; and maintain valve stability by preventing migrationof the valve into the atrium or ventricle.

In view thereof, disclosed herein are aspects of a valve prosthesiswhich is generally designed to include a frame including a first sectionhaving a radially repeating cell pattern and a localized concavedepression in a portion of the first section, a second section having aradially repeating cell pattern, and a valve body including a pluralityof leaflets attached to the frame in the second section.

In another exemplary embodiment, disclosed herein are aspects of amethod of forming a valve prosthesis frame which generally includesproviding a heat set mandrel having a circumferential concave portioncorresponding to a first section of the valve prosthesis frame, placingthe valve prosthesis frame on the heat set mandrel, providing acompression sleeve around the valve prosthesis frame to form a portionof the first section to the circumferential concave portion of the heatset mandrel while a second portion of the first section remainsundeformed, and heat treating the valve prosthesis frame to permanentlydeform the portion of the first section into a localized concaveportion.

In another exemplary embodiment, disclosed herein are aspects of amethod of treating a valve disorder in a patient's heart which generallyincludes collapsing a valve prosthesis including a frame having a firstsection and a second section onto a delivery system, the first sectionhaving a localized concave portion and a non-concave portioncircumferentially spaced on an axial location of the first section,delivering the delivery system and the valve prosthesis to a heart,expanding the valve prosthesis in the heart, and withdrawing thedelivery system from the heart.

BRIEF DESCRIPTION OF THE DRAWINGS/FIGURES

The accompanying figures, which are incorporated herein, form part ofthe specification and illustrate embodiments of a valve prosthesis frameand delivery system. Together with the description, the figures furtherserve to explain the principles of and to enable a person skilled in therelevant art(s) to make, use, and implant the valve prosthesis describedherein. In the drawings, like reference numbers indicate identical orfunctionally similar elements.

FIG. 1 is a side view of a valve prosthesis frame according to an aspectof this disclosure.

FIG. 2 is a front view of the valve prosthesis frame shown in FIG. 1rotated 90 degrees therefrom according to an aspect of this disclosure.

FIG. 3 is a close up side view of a valve prosthesis frame according toan aspect of this disclosure.

FIG. 4 is a front view of a valve prosthesis according to an aspect ofthis disclosure.

FIG. 5 is a side view of a valve prosthesis frame in a collapsedconfiguration attached to a delivery system according to an aspect ofthis disclosure.

FIG. 6 is a front view of the valve prosthesis frame shown in FIG. 5rotated 90 degrees therefrom, the valve prosthesis frame being shown ina collapsed configuration attached to a delivery system according to anaspect of this disclosure.

FIG. 7 is a side view of a valve prosthesis frame in a collapsedconfiguration attached to a delivery system according to an aspect ofthis disclosure.

FIG. 8 is a front view of a heat set mandrel.

FIG. 9 is a front view of a crimped frame mandrel according to an aspectof this disclosure.

FIG. 10 is a perspective view of a crimped frame mandrel and compressionsleeve according to an aspect of this disclosure.

FIG. 11 is a top view of a crimped frame mandrel and compression sleeveaccording to an aspect of this disclosure.

FIG. 12 is a side view of a valve prosthesis delivery system accordingto an aspect of this disclosure.

FIG. 13 is a top view of a valve prosthesis delivery system according toan aspect of this disclosure.

FIG. 14 is a sectional view of a portion of a valve prosthesis deliverysystem according to an aspect of this disclosure.

FIG. 15 is a sectional view of a portion of a valve prosthesis deliverysystem according to an aspect of this disclosure.

FIG. 16 is a side view of a valve prosthesis delivery system accordingto an aspect of this disclosure.

FIG. 17 is a sectional view of a portion of a valve prosthesis deliverysystem according to an aspect of this disclosure.

FIG. 18 is a sectional view of a portion of a valve prosthesis deliverysystem according to an aspect of this disclosure.

FIG. 19 is a schematic view of a valve prosthesis delivery systemaccording to an aspect of this disclosure.

FIG. 20 is a schematic view of a valve prosthesis delivery systemaccording to an aspect of this disclosure.

FIG. 21 is a schematic view of a valve prosthesis delivery systemaccording to an aspect of this disclosure.

FIG. 22 is a schematic view of a valve prosthesis delivery systemaccording to an aspect of this disclosure.

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description of a valve prosthesis frame anddelivery system refers to the accompanying figures that illustrateexemplary embodiments. Other embodiments are possible. Modifications canbe made to the embodiments described herein without departing from thespirit and scope of the present invention. Therefore, the followingdetailed description is not meant to be limiting.

The present invention is directed to a heart valve prosthesis having aself-expanding frame that supports a valve body. The valve prosthesiscan be delivered percutaneously to the heart to replace the function ofa native valve. For example, the valve prosthesis can replace a bicuspidor a tricuspid valve such as the aortic, mitral, pulmonary, or tricuspidheart valve.

In one aspect of the invention, the valve body comprises three leafletsthat are fastened together at enlarged lateral end regions to formcommissural joints, with the unattached edges forming the coaptationedges of the valve. The leaflets can be fastened to a skirt, which inturn can be attached to the frame. The upper ends of the commissurepoints define an outflow or proximal portion of the valve prosthesis.The opposite end of the valve at the skirt defines an inflow or distalportion of the valve prosthesis. The enlarged lateral end regions of theleaflets permit the material to be folded over to enhance durability ofthe valve and reduce stress concentration points that could lead tofatigue or tearing of the leaflets. The commissural joints are attachedabove the plane of the coaptation edges of the valve body to minimizethe contacted delivery profile of the valve prosthesis. The base of thevalve leaflets is where the leaflet edges attach to the skirt and thevalve frame.

Referring now to FIGS. 1-4, frame 100 is an exemplary aspect of thepresent invention. Frame 100 includes an inflow section 102, a valvesection 104, and an outflow section 106. Frame 100 also includes aplurality of cells 130 in the respective sections that can be differentsizes and/or shapes. Frame 100 can also include delivery systemattachments 120 to connect frame 100 onto a delivery system in acollapsed configuration for delivery into a patient's vasculature. Valve200 is connected to frame 100 to form valve prosthesis 10. Valve 200includes leaflets 210, commissures 220, and a skirt 230. In one aspectof the invention, valve 200 is connected to frame 100 in inflow section102 and valve section 104. The object of the present valve prosthesis isto mimic the native valve structure.

Frame 100 has a total height of approximately 30 mm to approximately 60mm. In the expanded configuration, the maximum diameter of inflowsection 102 can range from about 16 mm to about 36 mm, with a preferredrange of about 21 mm to about 33 mm. Inflow section 102 also has aheight of approximately 7 mm to approximately 14 mm. The diameter ofvalve section 104 can range from about 18 mm to about 26 mm, with apreferred range of about 20 mm to about 24 mm. Valve section 104 alsohas a height of approximately 7 mm to approximately 14 mm. The maximumdiameter of outflow section 106 can range from about 28 mm to about 45mm, with a preferred range of about 30 mm to about 38 mm. Outflowsection 106 also has a height of approximately 10 mm to approximately 25mm.

The plurality of cells 130 forming a cell pattern in frame 100 permitframe 100 to adapt to the specific anatomy of the patient, therebyreducing the risk of valve prosthesis migration and reducing the risk ofperivalvular leakage. In one aspect of the invention, inflow section 102of valve prosthesis 10 is disposed in the aortic annulus of thepatient's left ventricle.

Typically, heart valve prostheses aim to create laminar blood flowthrough the prosthesis in order to prevent lysis of red blood cells,stenosis of the prosthesis, and other thromboembolic complications.Outflow section 106 is designed to conform to a patient's anatomy and toanchor valve prosthesis 10 in the patient's ascending aorta to preventlateral movement or migration of valve prosthesis 10 due to normalmovement of the heart.

In one aspect of the invention, frame 100 includes a crimp, dent, and/orconcave depression 110 in a portion of frame 100. The term crimp will beused throughout to refer to the crimp, dent, or concave depression 110.Crimp 110 is provided so that when frame 100 is collapsed onto adelivery system, the region of frame 100 at crimp 110 is flexible aroundan axis perpendicular to the longitudinal direction. This flexibilitypermits the frame and delivery system to bend, flex, and/or kink as theframe and delivery system are advanced through a bend in a patient'svasculature. In one aspect of the invention, crimp 110 extendscircumferentially across approximately three cells 130 of frame 100. Inan alternate aspect of the invention, crimp 110 extendscircumferentially across approximately one cell 130 of frame 100 toapproximately four cells 130 of frame 100.

The outer diameter of frame 100 is reduced through crimp 110, as shownin FIGS. 1, 3, and 5-6. More particularly, a reduction in the outerdiameter of frame 100 due to crimps or localized concave depressions 110may be understood: by comparing an outer diameter OD_(E1) of expandedframe 100 through crimps 110 in FIG. 1 with an outer diameter OD_(E2) ofexpanded frame 100 through adjacent segments without crimps in FIG. 2,wherein the adjacent segments are the uncrimped or non-concave portionsthat circumferentially extend between crimps 110; and by comparing anouter diameter OD_(C1) of collapsed frame 100 through crimps 110 in FIG.5 with an outer diameter OD_(C2) of collapsed frame 100 through adjacentsegments without crimps in FIG. 6, wherein the adjacent segments are theuncrimped or non-concave portions that circumferentially extend betweencrimps 110. In one aspect of the invention, each crimp 110 reduces theouter diameter OD_(E1), OD_(C1) of frame 100 by approximately 1 mm toapproximately 3 mm as compared to an outer diameter of a portion offrame 100 that does not include a crimp 110. In one aspect of theinvention, each crimp 110 reduces the outer diameter of frame 100 byapproximately 1 mm. In an alternate aspect of the invention, each crimp110 reduces the outer diameter of frame 100 by approximately 2 mm. In analternate aspect of the invention, each crimp 110 reduces the outerdiameter of frame 100 by approximately 3 mm.

In the expanded configuration, crimp 110 can be difficult to visuallynotice because the reduction of the outer diameter of frame 100 due tocrimp 110 is relatively small compared to the outer diameter of frame100 in the expanded configuration. Therefore, crimp 110 will not affectthe function or placement of valve prosthesis 10 in the patient'sanatomy.

However, in the collapsed configuration, shown in FIGS. 5-6, theapproximately 1 mm to approximately 3 mm crimp is reduced in diameterwhile the overall diameter of the frame is reduced to a diameter ofapproximately 6 mm, or to the size of the inner diameter of the deliverysystem capsule containing the crimped frame and valve, as shown in FIGS.5 and 6. Crimp 110 reduces the outer diameter of a portion of frame 100and in the collapsed configuration, positions the crimped frame portiontowards the center of frame 100. In other words, crimp 110 pulls frame100 material in towards the center of frame 100, closer to the neutralaxis of bending. Thus, crimp 110 creates a flexible portion in frame 100in the collapsed configuration, thus allowing the delivery system andframe to bend, flex, and/or kink in a single plane and traverse a bendin a patient's vasculature during delivery of valve prosthesis 10.

As shown in FIGS. 1-3, crimp 110 can be positioned in outflow portion106 of frame 100. In an alternate aspect of the invention, crimp 110 canbe positioned in any portion of frame 100 to create flexibility at thatspecific longitudinal location of frame 100. In one aspect of theinvention, crimp 110 can be circumferentially spaced approximately 90degrees from delivery system attachments 120.

In an aspect of the invention, frame 100 can include two crimps 110, asshown in FIG. 1. In this aspect, crimps 110 are circumferentially spacedapproximately 180 degrees apart. As such, crimps 110 will facilitatebending, flexing, and/or kinking in a single plane during delivery.

In an alternate aspect of the invention, frame 100 can include three ormore crimps 110. In a further aspect of the invention, a plurality ofcrimps 110 can extend along the circumference of frame 100. In thisaspect, crimps 110 create an hourglass shape in frame 100. The hourglassshape allows frame 100 to bend, flex, and/or kink in multiple planesduring delivery of valve prosthesis 10. In the aspects of the inventionincluding two crimps 110 circumferentially spaced approximately 180degrees apart and/or a plurality of crimps 110, each crimp 110 reducesthe outer diameter of its respective portion of frame 100 in theexpanded configuration and in the collapsed configuration, as depictedby expanded outer diameter OD_(E1) through opposing crimps 110 in FIG.1and as depicted by collapsed outer diameter OD_(C1) through opposingcrimps 110 in FIG. 5.

In one aspect of the invention, crimp 110 is permanently heat set intoframe 100. In an alternate aspect of the invention, crimp 110 isbi-stable such that crimp 110 is present in the collapsed configurationof frame 100, but is not present in the expanded configuration of frame100.

As shown in FIGS. 5-7, frame 100 can be collapsed onto a delivery system300 including a pusher tube 310 and a central tube 330, each of whichare concentrically aligned and permit relative motion with respect toeach other. At a distal end of pusher tube 310 is a capsule 320 thatsurrounds the collapsed valve prosthesis 10 during delivery to theimplantation site. The capsule 320 restrains valve prosthesis 10 in theradial direction. During deployment, the capsule is withdrawn over thevalve prosthesis.

At a distal end of central tube 330 is a plunger assembly 332 whichincludes a hub 334, a tip 338, and attachment tabs 336. Tip 338facilitates the advancement of delivery system 300 through the patient'svasculature. Hub 334 includes one or more attachment tabs 336 forretaining valve prosthesis 10 on plunger assembly 332. Tabs 336 alsoprevent the pre-release of valve prosthesis 10 and assist in retainingvalve prosthesis 10 during recapture.

In the collapsed configuration, frame 100 attachments 120 connect ontoattachment tabs 336 on delivery system 300. Collapsed frame 100 abutsthe interior surface of capsule 320 and is thus maintained in acollapsed configuration on delivery system 300. As shown, crimp 110facilitates bending, flexing, and/or kinking of frame 100 around axis400.

Manufacture of frame 100 will now be described. Frame 100 can be lasercut from a solid tube of a self-expanding metal, such as Nitinol, with athin wall thickness. The laser cuts cells 130 into the nitinol tubeforming a cell pattern. After laser cutting is complete, the nitinoltube is expanded to increase the overall size and diameter of thenitinol tube. Nitinol is formable when it is brought to a coldtemperature. Therefore, to expand the nitinol tube, the nitinol tube isbrought to a cold temperature and a cylindrical expansion mandrel isinserted into the formable nitinol tube. The expanded nitinol tube isthen subject to a high temperature greater than 500 degrees centigrade.This high temperature cycle removes the stress and strain in the nitinoltube and effectively creates a new natural state for the expandednitinol tube. This expansion cycle is repeated several times with largerexpansion mandrels, each expansion step being within the strain limitsof the nitinol material. For the final expansion step, a shaped mandrelis inserted into the expanded nitinol tube. A typical shaped mandrel 410is shown in FIG. 8. Shaped mandrel 410 has the shape of a finishedframe. Referring now to FIGS. 9-11, mandrel 420 has a concave sectionmachined into it to allow for creation of crimp 110. Mandrel 420 isinserted into frame 100 and compression sleeve 430 is placed around theconcave section on mandrel 420. Compression spacers 440 are inserted inbetween compression sleeve 430 and frame 100 to force a portion of frame100 into the concave section of mandrel 420. After a final hightemperature cycle, frame 100 maintains the shape of mandrel 420including crimp 110 formed by the concave section of mandrel 420 andcompression spacers 440. Frame 100 then undergoes finishing processingand a valve 200 is sewn to frame 100.

FIGS. 12-15 illustrate an alternate delivery system design directed tofacilitate bending, flexing, and/or kinking as the frame and deliverysystem are advanced through a bend in a patient's vasculature. Deliverysystem 1300 includes a capsule 1320 having a first portion 1322 having acircular cross-section and a second portion 1324 having an ovalcross-section. In one aspect of the invention, delivery system 1300 canbe used with a frame that does not include a crimp. Instead of a crimp,the oval cross-section in second portion 1324 brings frame materialcloser towards the center of the frame and thus creates a flexibleregion in the frame. In other words, the oval cross section pulls framematerial in towards the center of the frame, closer to the neutral axisof bending. Thus, the oval cross-section in second portion 1324 createsa flexible portion in the frame in the collapsed configuration, thusallowing the delivery system and frame to bend, flex, and/or kink in asingle plane and traverse a bend in a patient's vasculature duringdelivery of valve prosthesis 10.

FIGS. 16-18 illustrate an alternate delivery system design directed tofacilitate bending, flexing, and/or kinking as the frame and deliverysystem are advanced through a bend in a patient's vasculature. Deliverysystem 2300 includes a capsule 2320 having a first portion 2322 havingan inner diameter with a circular cross-section and a second portion2324 having an inner diameter with an oval cross-section. The outerdiameter of first portion 2322 is equal to the outer diameter of secondportion 2324. In one aspect of the invention, delivery system 2300 canbe used with a frame that does not include a crimp. Instead of a crimp,the oval cross-section in the inner diameter of second portion 2324brings frame material closer towards the center of the frame and thuscreates a flexible region in the frame. In other words, the oval crosssection pulls frame material in towards the center of the frame, closerto the neutral axis of bending. Thus, the ovaled oval cross-section inthe inner diameter of second portion 2324 creates a flexible portion inthe frame in the collapsed configuration, thus allowing the deliverysystem and frame to bend, flex, and/or kink in a single plane andtraverse a bend in a patient's vasculature during delivery of valveprosthesis 10.

FIGS. 19-22 illustrate an alternate delivery system design directed tofacilitate bending, flexing, and/or kinking as the frame and deliverysystem are advanced through a bend in a patient's vasculature. Deliverysystem 3300 includes a capsule 3320 attached to the distal end of pushertube 3310. Hub 3506 is attached to a distal end of central tube 3330 andis attached to spacer tethers 3504 which are in turn attached to spacers3502. In one aspect of the invention, frame 3100 does not include acrimp. Spacers 3502 are placed on opposite sides of frame 3100 in thecollapsed configuration. Thus, instead of a crimp, delivery system 3300uses spacers 3502 to bring frame material closer towards the center offrame 3100 and thus create a flexible region in frame 3100. In otherwords, spacers 3502 pull frame material 3100 in towards the center offrame 3100, closer to the neutral axis of bending. Thus, spacers 3502create a flexible portion in the frame in the collapsed configuration,thus allowing the delivery system and frame to bend, flex, and/or kinkin a single plane and traverse a bend in a patient's vasculature duringdelivery of valve prosthesis 10.

During deployment of valve prosthesis 3100, capsule 3320 is withdrawnproximally over frame 3100, spacers 3502, and central tube 3330. Spacers3502 are not attached to capsule 3320. Therefore the shape of frame 3100including the flexible region imparted by spacers 3502 does not changeduring capsule 3320 withdrawal. As shown in FIGS. 21-22, after frame3100 is fully deployed, spacer tethers 3504 allow spacers 3502 to beretracted back into capsule 3320.

The valve prosthesis can replace the function of a tricuspid or bicuspidheart valve including the mitral valve, the aortic valve, the pulmonaryvalve, or the tricuspid valve. The valve can be delivered, for example,transfemorally, transeptally, transapically, transradially, ortransatrially.

Implantation of the valve prosthesis will now be described. As discussedabove, the valve prosthesis preferably comprises a self-expanding framethat can be compressed to a contracted delivery configuration onto aninner member of a delivery catheter. This frame design requires aloading system to crimp valve prosthesis 10 to the delivery size, whileallowing the proximal end of valve prosthesis 10 to protrude from theloading system so that the proximal end can be attached to tabs 336.

The valve prosthesis and inner member can then be loaded into a deliverysheath of conventional design. The delivery catheter and valveprosthesis can then be advanced in a retrograde manner through thefemoral artery and into the patient's descending aorta. The catheterthen is advanced, under fluoroscopic guidance, over the aortic arch,through the ascending aorta and mid-way across the defective aorticvalve. Once positioning of the catheter is confirmed, capsule 320 can bewithdrawn proximally, thereby permitting valve prosthesis 10 toself-expand.

As the valve prosthesis expands, it traps the leaflets of the patient'sdefective aortic valve against the valve annulus, retaining the nativevalve in a permanently open state. The outflow section of the valveprosthesis expands against and aligns the prosthesis within theascending aorta, while the inflow section becomes anchored in the aorticannulus of the left ventricle, so that the skirt reduces the risk ofperivalvular leaks.

Alternatively, the valve prosthesis can be delivered through atransapical procedure. In a transapical procedure, a trocar or overtubeis inserted into the left ventricle through an incision created in theapex of a patient's heart. A dilator is used to aid in the insertion ofthe trocar. In this approach, the native valve (e.g. the mitral valve)is approached from the downstream relative to the blood flow. The trocaris retracted sufficiently to release the self-expanding valveprosthesis. The dilator is preferably presented between the valveleaflets. The trocar can be rotated and adjusted as necessary toproperly align the valve prosthesis. The dilator is advanced into theleft atrium to begin disengaging the proximal section of the valveprosthesis from the dilator.

In an alternate aspect of the invention, the valve prosthesis can bedelivered through a transatrial procedure. In this procedure, thedilator and trocar are inserted through an incision made in the wall ofthe left atrium of the heart. The dilator and trocar are advancedthrough the native valve and into the left ventricle of heart. Thedilator is then withdrawn from the trocar. A guide wire is advancedthrough the trocar to the point where the valve prosthesis comes to theend of the trocar. The valve prosthesis is advanced sufficiently torelease the self-expanding frame from the trocar. The trocar can berotated and adjusted as necessary to properly align the valveprosthesis. The trocar is completely withdrawn from the heart such thatthe valve prosthesis self-expands into position and assumes the functionof the native valve.

The foregoing description has been presented for purposes ofillustration and enablement, and is not intended to be exhaustive or tolimit the invention to the precise form disclosed. Other modificationsand variations are possible in light of the above teachings. Theembodiments and examples were chosen and described in order to bestexplain the principles of the invention and its practical applicationand to thereby enable others skilled in the art to best utilize theinvention in various embodiments and various modifications as are suitedto the particular use contemplated. It is intended that the appendedclaims be construed to include other alternative embodiments of theinvention.

1-20. (canceled)
 21. A delivery system for implanting a valveprosthesis, the device comprising: an inner shaft assembly including ashaft and a valve prosthesis retainer hub; and a capsule slidablyreceived over the inner shaft assembly, wherein the capsule isconfigured to compressibly retain a self-expanding valve prosthesis, thecapsule having a distal portion having a circular cross-section and aproximal portion having an ovaled cross-section, wherein the proximalportion is configured to bend in a single plane at the ovaledcross-section during delivery of a self-expanding valve prosthesis. 22.The delivery system of claim 21, wherein the delivery device isconfigured to provide a delivery condition in which a self-expandingvalve prosthesis is compressed over the shaft of the inner shaftassembly and retained within the capsule.
 23. The delivery system ofclaim 22, wherein the delivery device is further configured to provide adeployment condition in which the capsule is proximally withdrawn over aself-expanding valve prosthesis.
 24. The delivery system of claim 21,wherein an outer diameter of the distal portion has the circularcross-section.
 25. The delivery system of claim 21, wherein an outerdiameter of the proximal portion has the ovaled cross-section.
 26. Thedelivery system of claim 21, wherein an inner diameter of the distalportion has the circular cross-section.
 27. The delivery system of claim21, wherein an inner diameter of the proximal portion has the ovaledcross-section.
 28. The delivery system of claim 21, wherein the proximalportion has an inner diameter having the ovaled cross-section and anouter diameter having a circular cross-section.
 29. The delivery systemof claim 28, wherein an outer diameter of the distal portion is the sameas the outer diameter of the proximal portion.